Husband of Pittsburgh doctor charged in her cyanide death arrested in W. Va.

University of Pittsburgh researcher Dr. Robert Ferrante, charged with criminal homicide in the death of his wife, UPMC neurologist Dr. Autumn Klein, was arrested in West Virginia and remains in custody there on Friday morning.

Ferrante, 64, was taken into custody Thursday evening by state police while he was traveling north on Interstate 77 near Beckley. He was arraigned late Thursday night and is being held in the Southern Regional Jail. A timetable for his return to Pittsburgh has not been set. (Watch video from Ferrante's arraignment)

Earlier Thursday, Pittsburgh police tried to arrest Ferrante in St. Augustine, Fla., where they believed he was staying with his sister. "When they arrived at the residence, they learned that Mr. Ferrante had left the residence, fled north in his vehicle, presumably driving back to Pittsburgh," Lt. Kevin Kraus said.

Kraus said police received information that Ferrante was in Florida at the beginning of the month, but they didn't expect him to leave the house in St. Augustine.

"We believe there was an event that caused him to leave the residence. When we got down there, we knew he was on the move, and that's when we felt it was prudent to locate and take him into custody," said Kraus, who wasn't sure if Ferrante was advised to leave the state.

In a news release, Allegheny County District Attorney spokesman Mike Manko said, "Our office was advised that counsel for the defendant had advised him of the warrant earlier today and told him to leave the state of Florida."

Ferrante's lawyer, Bill Difenderfer, said on Thursday morning that Ferrante was willing to come home to Pittsburgh and surrender. Difenderfer said he voluntarily turned over Ferrante's passport when his client went to Florida so he could show authorities that he was working with them.

"My client obviously wants to turn himself in and cooperate fully in terms of that, and he's anxious to have his day in court and prove his innocence, which I'm quite confident we'll be able to do," said Difenderfer, a few hours before the attempted arrest in Florida.

The Allegheny County medical examiner said on Thursday that Klein, 41, died from acute cyanide poisoning, and the manner of death was determined to be homicide, officially ruling out the possibility of suicide.

"The determination of the manner of death in this case as being a homicide was more complex and involved further laboratory testing along with extensive investigations by the Pittsburgh police and Office of the District Attorney to rule out other manners of death," Medical Examiner Dr. Karl Williams wrote in a media statement.(SLIDESHOW: The Autumn Klein case in photos)

Ferrante allegedly laced an energy supplement with cyanide before giving it to his wife hours after they exchanged text messages about how the supplement could help them conceive a child, according to a police complaint unsealed Thursday.

"Will it stimulate egg production too?" Klein asked about nine hours before she fell ill. He responded with a smiling emoticon.

Klein died April 20 after falling ill at her Oakland home three days earlier. She headed the women's neurology department at UPMC and taught at University of Pittsburgh School of Medicine, where her husband teaches neurology and is co-director of the Center for ALS Research.

Two days before his wife fell ill, Ferrante allegedly bought more than a half pound of cyanide using a university credit card, which police determined was the only substance he purchased not related to his work, according to an unidentified witness who helped him order "the best and purest cyanide he could get."

Witnesses then saw Ferrante drinking samples of creatine, the energy supplement referenced in the text messages, that he took from the lab and mixed with water and sugar. They told police Ferrante put the creatine in a large, resealable plastic bag.

According to the police complaint, paramedics who responded to a 911 call after Klein collapsed at home saw a small glass vial near a resealable plastic bag containing a white substance that Ferrante told them was creatine.

In May, Pittsburgh police were seen removing a computer, bags of evidence and two vehicles from Klein's home on Lytton Avenue.

During their investigation, city homicide detectives traveled to Boston, where the couple lived before moving to Pittsburgh two years ago. One person who police talked to was Ferrante's ex-wife, Diane DeMolles.

Reached by phone Thursday morning outside Boston, DeMolles said, "I can't believe it. This has been very upsetting to me. I just cannot believe it."

DeMolles said Ferrante has a temper, but she never saw him do anything that indicated he would be capable of murder. "Why would he do that? It just doesn't make sense to me," she said.

While the criminal complaint showed Klein may have been trying to get pregnant by Ferrante, he also suspected she was having an affair with a man in Boston.

That man told police he occasionally met Klein for dinner or drinks and that she complained Ferrante was controlling and not supportive of her job or her their daughter.

The man said Klein visited him in Boston overnight in June 2012 and attended a medical conference with him later that year in Atlanta and another in San Francisco in February.

Within weeks of her death, police determined Ferrante confronted Klein three times about whether she was having an affair. Other evidence shows Klein "intended to have a conversation with Ferrante and that Ferrante would 'not like the discussion,'" police said.